Type of supplement is a broad term that can refer to any number of substances taken to improve health or provide additional nutrition. The two crossword solutions for this term are IRON, a mineral found in many foods and supplements, and ONEADAY, a brand of multivitamin supplement. IRON is an essential mineral for the body, and is often taken as a supplement to prevent anemia. ONEADAY is a popular brand of multivitamin supplement that provides a range of vitamins and minerals to support overall health.